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Biomedical subjects

D M Jacobowitz

Publications and source records attributed to D M Jacobowitz.

At least 271 records · Page 15Linked to original sources
PubMed1976

Innervation of trigonal area of canine urinary bladder.

Adrenergic and cholinergic histochemical staining techniques and in vitro muscle strip responses to adrenergic and cholinergic stimulation and blockade have failed to demonstrate any neuromorphologic or neuropharmacologic differences between the musculature of the canine trigone and that of the underlying detrusor. There is no evidence to suggest that a functional potential could be attributed to the trigone separate from that of the related bladder base.

Acetylcholine↗
PubMed1976

Hyperthermia following self-stimulation of the median raphe in the rat.

Electrical self-stimulation (SS) in the median raphé of the rat but not in the locus coeruleus resulted in a dramatic rise of body temperature. This hyperthermia was facilitated by pretreatment with a inhibitor of serotonin uptake. The functional significance of the hyperthermia elicited by stimulation of the media raphé was discussed on the basis of the relationship between SS and primary reinforcers.

Animals↗
PubMed1976

The effect of bilateral lesions of the ventral noradrenergic bundle on endocrine-induced changes of tyrosine hydroxylase in the rat median eminence.

With the microdissection method of Palkovits, individual hypothalamic nuclei were removed from the brains of adult male rats, and the tyrosine hydroxylase (TH) activity of each nucleus was determined 7 days after gonadectomy or thyroidectomy. Following gonadectomy, TH activity increased significantly in the median eminence with no change in the periventricular (NPV), arcuate (NARC), and dorsomedial nuclei (NDM), or medial forebrain bundle (MF). Following thyroidectomy, TH activity increased significantly in all 5 hypothalamic nuclei examined. Placement of bilateral lesions in the ventral norepinephrine bundles resulted in a greater than an 85% fall in the dopamine-beta-hydroxylase activity of the median eminence, arcuate nucleus, and ventromedial nucleus, but had no effect on tyrosine hydroxylase activity measured in those same areas. Furthermore, placement of such lesions had no effect on the endocrine-induced increases of TH activity found in the median eminence following gonadectomy and thyroidectomy, but did prevent the increase of TH activity found in the NPV, NDM, and MFB following thyroidectomy. Three conclusions appear to be justified: (a) noradrenergic axons which innervate the median eminence, arcuate, and ventromedial nuclei course in the ventral norepinephrine bundles; (b) the TH content of noradrenergic neurons in the median eminence, arcuate nucleus, and ventromedial nuclei is quite small; and (c) the majority, if not all, of the endocrine-responsive catecholaminergic neurons in the median eminence are dopaminergic.

Animals↗
PubMed1976

Biochemical and histochemical studies of biogenic amines in spinal cord trauma.

Highly sensitive enzymatic assays, microdissection techniques, and histochemical methods were used to investigate the effects of blunt trauma on rabbit spinal cord serotonin, norepinephrine, and dopamine concentrations. Within 5 minutes after trauma, norepinephrine and serotonin in gray matter decreased considerably at the lesion center. In white matter, norepinephrine decreased or was unchanged, but at the lesion edges serotonin increased. No changes in dopamine concentration were detected. Substantial changes in monoamines do occur after spinal cord trauma and serotonin may play a role in injury development.

Animals↗
PubMed1975

The effect of two diverse inhalation anesthetic agents on serotonin in discrete regions of the rat brain.

Sensitive radioisotopic enzymatic methods were used to determine 5-HT levels in 16 different regions of brain from rats anesthetized for 90-105 min with 1% halothane or 18% cyclopropane. These two anesthetics were chosen because of their differing effects on the electroencephalogram and on the cardiovascular and respiratory systems. 5-HT levels in the nucleus amygdaloideus centralis, substantia nigra, and nucleus centralis superior were increased after administration of either anesthetic, but only anesthesia with cyclopropane was associated with an increase in 5-HT level in the nucleus raphe dorsalis. The changes in levels of transmitter does not distinguish cause from effect of anesthesia, and further experiments are needed to delineate what role, if any, the specific areas play in muscle relaxation, analgesia, sleep or anesthesia.

Amygdala↗
PubMed1975

Localized catecholamine storage associated with granules in murine neuroblastoma cells.

Catecholamine storage was examined in cultures of the murine neuroblastoma cell line, N-TD6, using histofluorescence, electron microscopic, isotopic and radioautographic criteria. This line was originally derived from uncloned, C1300 tumor cells by selection in tyrosine deficient medium. N-TD6 cells possess both tyrosine hydroxylase (tyrosine-3-monooxygenase, EC 1.14.16.2) and dopamine beta-hydroxylase (dopamine beta-monooxygenase, EC 1.14.17.1) activities. When examined for paraformaldehyde-induced histofluorescence, a small percentage of cells in the population show intense catecholamine fluorescence, often localized within discrete regions of the cellular processes. Electron microscopic examination of these cells reveals both electron lucent vesicles and more frequent, electron dense granules, 50-70 nm and 100-300 nm in diameter, respectively. The distribution of these granules and vesicles varies, but they appear most numerous near the cell surface, along processes and within process endings. By labeling cells with [3H]dopamine and then allowing the cells to release unbound label in the presence of unlabeled dopamine, the localization of catecholamine stores was visualized by radioautographic techniques. While a variety of intracellular distribution of radioactivity were observed, the most prominent concentrations were found in the processes and their terminals; no labeled material was retained when reserpine was present during uptake. The topographic coincidence of granules, catecholamine fluorescence and [3H]dopamine retention in these neuroblastoma cells suggests that catecholamines are stored within these granules in a manner analogous to that observed in normal adrenergic neurons.

Animals↗
PubMed1975

Central adrenergic neurons in DOCA-salt hypertension.

The effects of various doses of 6-hydroxydopamine (6-OHDA) injected into the hypothalamus on DOCA-salt-induced hypertension were studied. The development of hypertension was prevented in the group treated with the highest dose of 6-OHDA, and the onset of hypertension was delayed in a dose-dependent fashion in the groups treated with the lower doses of 6-OHDA. Catecholamine histofluorescence observations showed that the cannula tips placed the drug lateral to the third ventricle. The most prominent change observed was a marked unilateral reduction in the fluorescence of the dopaminergic nerves of the caudate-putamen and in the number of cell bodies in the substantia nigra. These results suggest possible sites of central aminergic control of blood pressure.

Animals↗